The aim of the proposed study is a. to challenge the widely accepted tenet that adult bone loss is inevitable, b. to prove that there are individuals in aging populations, in whose life styles, elements of good health, appropriate nutrition and an adequate level of physical activity converge to create an internal environment supportive of positive bone remodelling, and c. to provide rationale for the shift of emphasis in the management of osteoporosis from ineffective therapy to prophylaxis. To this end radial bone densities in postmenopausal women, age 50 -65, will be determined yearly for a period of 3 years. Bone density measurements will be carried out with CAT scanner (Computerized Axial Tomography) whose greater sensitivity and accuracy allows smaller changes in bone density to register as significant; this makes the proposed longitudinal study timely because it permits reduction in the time scale necessary for meaningful results to register. The percentage of subjects in the studied population maintaining stable (or incremental) bone densities during the 3 years of the study will be determined; association between bone densities and calcium intakes as well as levels of physical activity will be examined.